THE COTTOIT STALK-BORER. 65 



As has been stated bj^ Doctor Howard, it is the larva of the borer 

 that works in the cotton stalk. It confines its attack to the pith of the 

 plant. The amount of injurj^ depends upon the size of the plant and 

 the number of borers. The writer found one plant about 3 feet high 

 at Yoakum which contained eight larvae, and which showed four 

 emergence holes. The twelve borers had eaten out all the pith from 

 the smallest branches to 3 inches below the surface of the ground in 

 the tap-root. The small twigs were onlj^ thin shells and crumpled like 

 paper between the fingers. 



Nearly all infested plants showed unmistakable evidence of previous 

 injury, yet the comparativel}' fresh and healthy condition of a few 

 stalks points to the probability of an occasional attack upon perfectly 

 healthy stalks. In the field showing an infestation of 20 to 25 per 

 cent of its stalks it was estimated that the injured stalks had borne 

 at least 80 per cent as much cotton to a stalk as had the uninjured 

 ones. If it is true that the borer attacks only such stalks as are dis- 

 eased or otherwise injured, then only a little damage can be attributed 

 to it; yet the borers attack, added to the injury due to disease, must 

 hasten the death of the plant and thereb}" lessen the number of bolls 

 to mature. 



NATURAL ENEMIES. 



From material collected at Yoakum, Tex., on October 28 two para- 

 sites of Ataxia crypta were hved. One, Heterospilus websteri K^xn.^ 

 had entireh^ covered the pupa of A. cryjyta with its cocoons. In the 

 majority of cases, however, this parasite had spun its cocoon after 

 crawling awa}^ from the body of its host. Several masses of these 

 cocoons were found with no trace of either the larva or pupa of ^4. 

 crypta. visible, and in one instance the larv^ of this parasite were 

 found in a hollow cotton stalk and no form of A. crypta near. The 

 second parasite belongs to the genus Etroxys and is a new species. 

 There is some doubt that this species is a parasite upon Ataxia, but 

 since it is parasitic upon beetles and its pupa? were found in a stalk 

 bored out by A. crypta^ it is here placed on record as a parasite of the 

 latter. 



REMEDY. 



If at any time the injury by the insect should l^ecome serious the 

 numbers of the borer can be easily reduced b}^ destroying the infested 

 stalks early in the fall. The time of destruction must, of course, vary 

 in different localities, but it should be as earl}- in October as possible 

 for the latitude of Yoakum. By October 28 not more than 10 per 

 cent, of the borers had emerged. If the stalks had been destroyed 

 early in October very few borers would have escaped. To obtain the 

 best results, stalks should not be cut but plowed out, for many of the 



